During 2005, GSC and California State University, Long Beach (CSULB) conducted several notable small launch vehicle R&D activities through their partnership in the California Launch Vehicle Education Initiative. Using a single-chamber, liquid-propellant, annular aerospike engine concept developed by CSULB, the GSC/CSULB team validated the basic design and ignition sequence with a successful static fire test at the Reaction Research Society's Mojave Test Area (MTA) in June 2003. The team then mounted one of these 4,444-newton thrust LOX/ ethanol ablative engines onto their Prospector 2 vehicle and proceeded to conduct the first-ever powered liquid-propellant aerospike flight test at the MTA in September 2003. In response to several issues observed during that flight, modifications were made to the engine fabrication process. Another flight test with the Prospector 4 vehicle followed in December 2003. Performance was entirely nominal, resulting in complete recovery of the vehicle and key trajectory data.
Thanks. The air pressure is about 85% of sea level pressure at that altitude. Maybe that's enough to get some data about how the engine responds, but it's nothing like a real launch, and I think it's borderline fair for Tim Dodd to say these that "none have ever really flown" in the context of orbital rocketry.
I think Tim didn't know about that launch, that's why decided to add to the discussion. Not having data is not the same as not having flown; not only the flight has symbolic value but also, I'm sure, the flight serves as an incentive to all participants, especially students. 1.3 km altitude for a liquid fuel rocket is a very real launch, believe me, for amateur participants.
In the context of the video, which focused on technical details, I personally don't think the symbolic or incentive value is relevant. I'm glad you raised the point though.
http://www.astronautix.com/g/garveyaerospike.html
During 2005, GSC and California State University, Long Beach (CSULB) conducted several notable small launch vehicle R&D activities through their partnership in the California Launch Vehicle Education Initiative. Using a single-chamber, liquid-propellant, annular aerospike engine concept developed by CSULB, the GSC/CSULB team validated the basic design and ignition sequence with a successful static fire test at the Reaction Research Society's Mojave Test Area (MTA) in June 2003. The team then mounted one of these 4,444-newton thrust LOX/ ethanol ablative engines onto their Prospector 2 vehicle and proceeded to conduct the first-ever powered liquid-propellant aerospike flight test at the MTA in September 2003. In response to several issues observed during that flight, modifications were made to the engine fabrication process. Another flight test with the Prospector 4 vehicle followed in December 2003. Performance was entirely nominal, resulting in complete recovery of the vehicle and key trajectory data.